CN118144575A

CN118144575A - Braking energy recovery control method, system, vehicle, electronic equipment and medium

Info

Publication number: CN118144575A
Application number: CN202410589501.1A
Authority: CN
Inventors: 张立亮; 于善勇; 郝占武
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2024-05-13
Filing date: 2024-05-13
Publication date: 2024-06-07

Abstract

The invention discloses a braking energy recovery control method, a braking energy recovery control system, a vehicle, electronic equipment and a medium, and relates to the technical field of vehicles; the braking energy recovery control method comprises the following steps: in the braking energy recovery process of a braking system of a vehicle, if the requirement of switching a driving mode of the vehicle from a four-drive mode to a two-drive mode is received, judging whether a power system fails; if the power system has no fault, judging whether the current braking energy recovery process is finished or not, and recording the switching requirement of a driving mode; and if the current braking energy recovery process is finished, responding to the switching requirement of the driving mode. The invention can avoid the problems of deceleration loss or vehicle shrugging caused by the fact that the recovery torque of the motor is instantaneously reduced and the brake hydraulic pressure cannot be timely supplemented in the process of switching from the four-wheel drive mode to the two-wheel drive mode, thereby improving the driving safety of the vehicle and the recovery efficiency of the brake energy.

Description

Braking energy recovery control method, system, vehicle, electronic equipment and medium

Technical Field

The invention relates to the technical field of vehicles, in particular to a braking energy recovery control method, a braking energy recovery control system, a vehicle, electronic equipment and a medium.

Background

For a two-motor four-wheel drive vehicle, in order to meet different performance requirements of a driver on a power system, a power disengaging device is usually installed so as to switch a driving mode of the vehicle, so that the driver can enable different driving modes during running of the vehicle. In addition, the vehicle adopts the torque recovery technology of the motor, a large amount of braking energy can be recovered and converted into electric energy to be stored in the battery, so that the energy utilization rate is improved, the endurance mileage of the vehicle is prolonged, and the energy consumption is reduced.

If the switching process of the driving mode of the vehicle is coupled with the braking energy recovery process of the vehicle, when the driving mode is switched from the four-wheel drive mode to the two-wheel drive mode in the braking process, the recovery torque of the motor is instantaneously reduced, and at this time, the braking hydraulic pressure cannot be timely supplemented, so that the situation of deceleration loss or vehicle shrugging occurs. Therefore, how to recover braking energy as much as possible under the condition of ensuring normal switching of driving modes and braking safety is a technical problem which needs to be solved by the existing four-wheel drive new energy automobile.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a control method, a system, a vehicle, electronic equipment and a medium for recovering braking energy, which can avoid the problems that deceleration is lost or the vehicle tows due to the fact that the recovery torque of a motor is instantaneously reduced and the braking hydraulic pressure cannot be timely supplemented in the process of switching from a four-wheel drive mode to a two-wheel drive mode, thereby improving the driving safety of the vehicle and the efficiency of recovering the braking energy.

An embodiment of a first aspect of the present invention provides a braking energy recovery control method, including the steps of:

in the braking energy recovery process of a braking system of a vehicle, if the requirement of switching a driving mode of the vehicle from a four-wheel drive mode to a two-wheel drive mode is received, judging whether a power system fails;

If the power system has no fault, judging whether the current braking energy recovery process is finished or not, and recording the switching requirement of a driving mode;

and responding to the switching requirement of the driving mode if the current braking energy recovery process is finished.

The braking energy recovery control method according to the embodiment of the first aspect of the invention has at least the following beneficial effects: in the process that the vehicle runs in a four-wheel drive mode, a request for braking energy recovery is received, and braking deceleration and braking energy recovery are carried out on the vehicle; in the braking process, if a driving mode switching requirement of the vehicle is received so as to switch the driving mode from a four-wheel driving mode to a two-wheel driving mode, judging whether a power system of the vehicle has a fault condition or not before executing the driving mode switching; if the power system has no fault problem, judging whether the current braking energy recovery process is finished or not; if the brake pedal is still not released, the current braking energy recovery process is continued, so that the driving mode is not switched temporarily, and the switching requirement of the driving mode is recorded, so that the braking deceleration is not lost, the situation that the vehicle rises is avoided, the driving safety of the vehicle is improved, and meanwhile, the braking energy can be recovered as much as possible, and the energy consumption of the vehicle is reduced; if the brake pedal is released, the current braking energy recovery process is finished, then the switching requirement of the driving mode recorded before is executed, and the four-driving mode is switched to the two-driving mode, so that the speed reduction of the vehicle is not influenced in the switching process of the driving mode, and the safety risk is avoided.

In some embodiments of the present invention, the responding to the switching requirement of the driving mode includes the following steps:

Transmitting a command for a disconnection action to a power disconnection device of the vehicle so that one of two motors of the power system is in an operating state and the other is in a stopped state;

the recovery torque capacity of the motor in the running state is set to the recovery torque limit value, and the recovery torque capacity of the motor in the stopped state is set to zero.

In some embodiments of the present invention, the responding to the switching requirement of the driving mode further includes the steps of:

In the disconnection process of the power disconnecting device, if a request for braking energy recovery is received, setting the current torque proportionality coefficient of the motor in the running state to be 100%, and setting the current torque proportionality coefficient of the motor in the stopping state to be 0;

Judging whether the target braking torque of the braking system is larger than the recovery torque limit value of the motor in the running state;

if yes, determining the recovery torque limit value as the execution torque of the motor in the running state, and determining a hydraulic compensation torque according to the difference value between the target braking torque and the recovery torque limit value;

And if not, determining the target braking torque as the execution torque of the motor in the running state.

In some embodiments of the present invention, after the determining whether the power system is faulty, the braking energy recovery control method further includes the steps of:

If the power system is faulty, sending a command of disconnection to a power disconnecting device of the vehicle so as to stop a faulty motor of the power system, operating a non-faulty motor of the power system, and setting a recovery torque capacity state of the faulty motor as a fault;

clearing the execution torque of the failed motor and sending a hydraulic braking command to compensate for the reduced recovery torque.

In some embodiments of the present invention, after the determining whether the current braking energy recovery process is finished, the braking energy recovery control method further includes the steps of:

If the current braking energy recovery process is not finished, determining sub-target braking torque of each motor according to target braking torque of the braking system and current torque proportion coefficients of two motors of the power system;

judging the sizes of sub-target braking torque and recovery torque limit values of each motor;

If the sub-target braking torque is larger than the recovery torque limit value, determining the recovery torque limit value as the execution torque of the corresponding motor, and determining a hydraulic compensation torque according to the difference between the sub-target braking torque and the recovery torque limit value;

And if the sub-target braking torque is smaller than or equal to the recovery torque limit value, determining the sub-target braking torque as the execution torque of the corresponding motor.

In some embodiments of the present invention, the determining whether the current braking energy recovery process is finished includes the following steps:

In the current braking energy recovery process, monitoring whether a brake pedal is released or not in real time;

if yes, judging that the current braking energy recovery process is finished;

If not, judging that the current braking energy recovery process is not finished.

In some embodiments of the present invention, before the determining whether the power system fails, the braking energy recovery control method further includes the steps of:

Monitoring a current driving mode in real time;

judging whether the current driving mode is a two-drive mode or not;

if yes, setting the recovery torque capacity of the motor in the running state of the power system as a recovery torque limit value, and setting the recovery torque capacity of the motor in the stopping state of the power system as zero;

if not, the recovery torque capacity of the two motors of the power system is set as the recovery torque limit value.

In some embodiments of the present invention, after setting the recovery torque capacity of the motor in the running state of the power system to a recovery torque limit value and setting the recovery torque capacity of the motor in the stopped state of the power system to zero, the braking energy recovery control method further includes the steps of:

in the braking energy recovery process of a braking system of a vehicle, if the requirement of switching a driving mode of the vehicle from a two-drive mode to a four-drive mode is received, responding to the switching requirement of the driving mode, and keeping the recovery torque capacity of two motors of the power system unchanged;

And when the driving mode is switched, adjusting the recovery torque capacity of one motor of the power system from zero to a recovery torque limit value.

In some embodiments of the present invention, after the driving mode is switched, the braking energy recovery control method further includes the steps of:

And if the current braking energy recovery process is not finished, determining the execution torque of the two motors according to the recovery torque limit values of the two motors of the power system, the current torque proportional coefficient and the current target braking torque of the braking system.

Embodiments of the second aspect of the present invention provide a braking energy recovery control system including:

The judging unit is used for judging whether the power system fails or not when receiving the requirement of switching the driving mode of the vehicle from the four-wheel drive mode to the two-wheel drive mode in the braking energy recovery process of the braking system of the vehicle; and is used for judging whether the current braking energy recovery process is finished if the power system has no fault;

The recording unit is used for recording the switching requirement of the driving mode when judging whether the current braking energy recovery process is finished or not;

and the response unit is used for responding to the switching requirement of the driving mode if the current braking energy recovery process is finished.

An embodiment of a third aspect of the present invention provides a vehicle comprising a vehicle body and a braking energy recovery control system according to an embodiment of the second aspect, the braking energy recovery control system being provided on the vehicle body.

An embodiment of a fourth aspect of the present invention provides an electronic device, including:

At least one processor; and

A memory communicatively coupled to the at least one processor; wherein the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the braking energy recovery control method as an embodiment of the first aspect.

An embodiment of a fifth aspect of the present invention provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements a braking energy recovery control method as in the embodiment of the first aspect.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

FIG. 1 is a flow chart of a braking energy recovery control method according to an embodiment of the present invention;

Fig. 2 is a schematic flowchart of step S13 in the braking energy recovery control method according to the embodiment of the present invention;

FIG. 3 is a schematic flow chart of step S13 in a braking energy recovery control method according to another embodiment of the present invention;

FIG. 4 is a flow chart of a braking energy recovery control method according to another embodiment of the present invention;

FIG. 5 is a flow chart of a braking energy recovery control method according to another embodiment of the present invention;

fig. 6 is a schematic flowchart of step S12 in the braking energy recovery control method according to the embodiment of the present invention;

fig. 7 is a schematic flow chart before step S11 in the braking energy recovery control method according to the embodiment of the present invention;

Fig. 8 is a schematic flow chart before step S11 in a braking energy recovery control method according to another embodiment of the present invention;

fig. 9 is a schematic flow chart before step S11 in a braking energy recovery control method according to another embodiment of the present invention;

FIG. 10 is a schematic diagram of a braking energy recovery control system provided in accordance with an embodiment of the present invention;

fig. 11 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In the description of the present invention, it should be understood that if a feature of "first" or "second" is defined, it may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

For a two-motor four-wheel drive vehicle, in order to meet the requirements of drivers on different performances of a power system, the power system on the vehicle is usually provided with a power disengaging device, and the switching work of a vehicle driving mode is performed through the clutch action of the power disengaging device, so that the drivers can start different driving modes in the running process of the vehicle, and generally, the driving modes comprise an economic mode and a movement mode.

Specifically, when the vehicle is normally traveling in the economy mode, in order to reduce the energy consumption during the traveling of the vehicle, the drive mode of the vehicle is generally set to the two-drive mode in the economy mode. However, if the driver switches the driving mode from the economy mode to the sport mode or the driver increases the opening degree of the accelerator pedal in a short time during running, at this time, the driver needs the vehicle to have stronger power performance, and then the driving mode of the vehicle is switched from the two-drive mode to the four-drive mode.

If the driver switches the driving mode from the sport mode to the economy mode, or if the opening degree of the accelerator pedal is always low (below a certain set value) or the accelerator pedal is in a released state, at this time, in order to reduce the energy consumption during the running of the vehicle, it is necessary to switch the driving mode from the four-wheel drive mode to the two-wheel drive mode. In addition, if the vehicle is traveling on a wet road surface, in order to ensure good traveling stability and climbing performance of the vehicle, it is necessary to switch or maintain the driving mode of the vehicle to the four-wheel drive mode.

On the other hand, the existing vehicles basically adopt the torque recovery technology of the motor, a large amount of braking energy can be recovered and converted into electric energy to be stored in the battery, and the energy is released when the vehicle needs, so that the energy utilization rate of the vehicle can be effectively improved, the endurance mileage of the vehicle is prolonged, and the energy consumption of the vehicle is reduced. Currently, the braking energy recovery function has become standard on new energy automobiles. When the braking energy recovery work is carried out, the safety and stability of the vehicle braking are required to be ensured, and the efficiency of the braking energy recovery is improved.

If the switching process of the vehicle driving mode is coupled with the braking energy recovery process of the vehicle, how to recover the braking energy as much as possible under the condition of ensuring the normal switching of the vehicle driving mode and the safety of the vehicle braking is an important technical problem which is urgently needed to be faced and solved by the existing four-wheel drive new energy automobile.

For example, when the driver not only recovers braking energy in the braking process, but also switches the driving mode from the four-wheel driving mode to the two-wheel driving mode (such as adopting a rear-wheel driving mode), the recovery torque of the motor is changed from acting on two shafts to acting on one shaft, and then the recovery torque of the motor is instantaneously reduced; because the driving torque is controlled by the power system, the braking electric control system senses the switching of the driving modes through the motor state of the power system and needs to supplement braking force through a hydraulic braking function; at this time, the brake hydraulic pressure cannot be timely supplemented, so that the situation that deceleration is lost or the vehicle tows occurs, and the comfort and safety of driving are affected.

Therefore, there is a strong need for a vehicle control strategy that not only ensures that no deceleration loss or vehicle cocking occurs during drive mode switching, but also improves braking energy recovery efficiency.

Based on the above, the embodiment of the invention provides a control method, a system, a vehicle, electronic equipment and a medium for recovering braking energy, which can avoid the problems that deceleration is lost or the vehicle tows due to the fact that the recovery torque of a motor is not timely reduced in the process of switching from a four-wheel drive mode to a two-wheel drive mode, so that the driving safety of the vehicle and the efficiency of recovering braking energy are improved.

A braking energy recovery control method, system, vehicle, electronic device, and medium according to an embodiment of the present invention are described below with reference to fig. 1 to 11.

As shown in fig. 1, the braking energy recovery control method according to the embodiment of the first aspect of the present invention includes the following steps:

Step S11: in the braking energy recovery process of a braking system of a vehicle, if the requirement of switching a driving mode of the vehicle from a four-wheel drive mode to a two-wheel drive mode is received, judging whether the power system fails.

Step S12: if the power system has no fault, judging whether the current braking energy recovery process is finished or not, and recording the switching requirement of the driving mode.

Step S13: and if the current braking energy recovery process is finished, responding to the switching requirement of the driving mode.

It will be appreciated that the vehicle is provided with a motor and power disconnect (i.e. clutch) driven independently of the front and rear axles, and that switching between the four-drive mode and the two-drive mode, or vice versa, may be accomplished by the power disconnect being disengaged or engaged under certain conditions.

In the four-wheel drive mode, both motors are operated and provide driving power for the vehicle. In the two-drive mode, the driving power can be provided in a front-drive mode or a rear-drive mode. In the front drive mode, the motor corresponding to the front shaft runs to participate in running work, and the motor corresponding to the rear shaft stops running. In the rear drive mode, the motor corresponding to the front axle is stopped, and the motor corresponding to the rear axle is operated and provides power for the vehicle.

When a driver presses a brake pedal and the power system has the capability of recovering braking force of the motor, the power electric control system can send out data of the maximum value (namely the recovery torque limit value) of the recovery torque of the current motor, after the brake electric control system detects the condition triggered by the recovery function of the braking energy, the brake electric control system can send out a request of the recovery torque of the motor, at the moment, the request value of the recovery torque of each motor can be smaller than or equal to the maximum value of the recovery torque of the current motor, and the current recovery torque of the brake is distributed on the front shaft and the rear shaft of the vehicle through the torque proportion coefficient, so that the recovery torque distribution value of each motor is obtained.

The motor recovery torque limit is determined by both the battery and the motor itself, and the current brake recovery torque (i.e., the target brake torque) can be determined based on the driver-set recovery strength and deceleration correspondence. The recovered torque distribution value of the corresponding motor can be obtained by the product of the target braking torque and the corresponding torque proportional coefficient.

If the recovered torque distribution value of the motor is larger than the recovered torque limit value, the motor cannot meet the speed reduction regulation requirement of the vehicle, and at the moment, the recovered torque limit value is determined to be the execution torque of the motor, namely, the motor generates negative torque under the condition of ensuring the safety of the motor and a battery at the moment, and mechanical energy during braking is converted into electric energy; meanwhile, a hydraulic compensation torque of the vehicle body stabilization system is determined according to the difference between the recovered torque distribution value and the recovered torque limit value, and the hydraulic compensation torque is determined as an execution torque of the vehicle body stabilization system.

If the recovered torque distribution value is less than or equal to the recovered torque limit, the deceleration adjustment requirement of the vehicle can be satisfied, at which time the recovered torque distribution value is determined as the execution torque of the motor, while the vehicle body stabilization system is not required to operate to provide the hydraulic compensation torque.

The recovery torque limit of the electric machine may be determined by the smaller of the first torque limit and the second torque limit. The first torque limit value is a peak torque of the motor under the maximum allowable charging power of the battery, and is determined according to the charging power limit value of the battery and the rotating speed of the motor. The second torque limit is a peak torque of a maximum output power of the motor. It will be appreciated that in the prior art, the power electronic control system is able to obtain and issue a recovery torque limit for the motor and the brake electronic control system is able to obtain and issue a target brake torque.

For a better illustration, assuming a current brake recovery torque of 100, the front axle has a torque scaling factor of 30%, then the rear axle has a torque scaling factor of 70%, then the motor recovery torque split for the front axle motor is 30 and less than or equal to its recovery torque limit, and for the rear axle motor is 70 and less than or equal to its recovery torque limit. If the recovered torque distribution value is greater than the recovered torque limit, braking force compensation by hydraulic torque is required. Of course, the torque proportionality coefficients of the two motors of the front and rear shafts may be 50% respectively, and the specific torque proportionality coefficient may be set according to the actual situation, and is not particularly limited herein.

It will be appreciated that, in step S11, if the driver depresses the brake pedal during the running of the vehicle in the four-wheel drive mode, the control system of the vehicle receives a request for braking energy recovery, and performs braking deceleration and braking energy recovery on the vehicle. During this braking energy recovery process, if the control system receives a drive mode switching request from the vehicle to switch the drive mode from the four-drive mode to the two-drive mode, it is necessary to determine whether a failure condition has occurred in the vehicle's powertrain before the powertrain performs the drive mode switching via the power disconnect device.

If the power system has no fault problem, the braking energy recovery work can be completed through the two motors of the front shaft and the rear shaft in the braking process, and the braking energy recovery efficiency is improved. If the power system fails, the two motors of the front shaft and the rear shaft cannot be used for recovering braking energy.

In step S12, if it is detected that the state of the power system is good and there is no trouble problem, it is necessary to determine whether the current braking energy recovery process has ended. As shown in fig. 6, the step of determining whether the current braking energy recovery process is finished specifically includes the following steps:

Step S121: in the current braking energy recovery process, whether the brake pedal is released or not is monitored in real time.

Step S122: if yes, judging that the current braking energy recovery process is finished.

Step S123: if not, judging that the current braking energy recovery process is not finished.

The control system monitors the state of the brake pedal in real time during the period from when the driver depresses the brake pedal to when the brake pedal is fully released, and specifically, during this braking cycle, it is known whether the brake pedal is in a released state by detecting the opening degree of the brake pedal.

If the braking cycle is not finished, i.e. the brake pedal is not released, the current braking energy recovery process is continued, and the two motors of the front and rear shafts still perform braking energy recovery operation. If the driving mode is switched in the braking energy recovery process, one of the motors is driven to stop providing driving power through the power disengaging gear, at the moment, the recovery torque of the motor is instantaneously reduced, the braking hydraulic pressure cannot be timely supplemented, and the deceleration loss is caused.

In order to ensure that the braking deceleration is not lost, the situation that the vehicle rises is avoided, the driving safety of the vehicle is improved, braking energy is recovered as much as possible, and the energy consumption of the vehicle is reduced, so that the driving mode is not switched temporarily in the braking cycle, and meanwhile, the control system records the switching requirement of the driving mode. The data of the switching requirement is temporarily stored in the control system to wait for the end of the braking energy recovery process.

In step S13, if it is detected that the driver releases the brake pedal completely, it indicates that the braking energy recovery process is finished, and the two motors of the front and rear axles are no longer recovering braking energy, so that the control system executes the switching requirement of the driving mode recorded before, and the power system stops one of the motors through the disconnection of the power release device, thereby realizing the switching of the driving mode from the four-driving mode to the two-driving mode.

By adopting the control strategy, the embodiment of the invention ensures that the deceleration of the vehicle is not influenced in the process of switching the driving mode, avoids the occurrence of safety risks, and recovers more braking energy under the condition of ensuring the braking safety of the vehicle, thereby being capable of solving the problem of how to safely and efficiently interact the driving mode switching function and the braking energy recovery function in the running process of the vehicle.

As shown in fig. 1 and 2, in step S13, the steps in response to the switching requirement of the driving mode specifically include the following steps:

Step S131: a command to the power disconnect of the vehicle is sent to disengage the action to bring one of the two motors of the powertrain to an operating state and the other to a stopped state.

Step S132: the recovery torque capacity of the motor in the running state is set to the recovery torque limit value, and the recovery torque capacity of the motor in the stopped state is set to zero.

When the braking energy recovery process is finished, the control system sends a command for disconnecting the power disconnecting device so as to start the driving mode to switch from the four-driving mode to the two-driving mode. The power disengaging device in the power system can perform corresponding actions after receiving the instruction, so that one of the two motors of the front shaft and the rear shaft is driven to keep running, power is provided for the vehicle, and the other motor stops running. At this time, the precursor mode or the post-drive mode may be selected according to the needs of the driver. Generally, the power electronic control system sets the back-driving mode as a priority.

The motor in the running state is set as a working motor, and the motor in the stopped state is set as a standby motor. When the state of the power system is displayed as that the four-wheel drive mode is being switched to the two-wheel drive mode, the power electric control system sets the recovery torque capacity of the working motor to an actual capacity value, namely, the recovery torque limit value of the working motor, and sets the recovery torque capacity of the standby motor to zero. At this time, if the brake electric control system sends out a request for braking recovery torque, the brake energy of the vehicle is recovered by the working motor and converted into electric energy, and the standby motor does not participate in the braking energy recovery work.

Further, as shown in fig. 1, 2 and 3, in step S13, the step of responding to the switching requirement of the driving mode specifically further includes the following steps:

Step S133: during the disconnection of the power disconnection device, if a request for braking energy recovery is received, the current torque proportionality coefficient of the motor in the running state is set to 100%, and the current torque proportionality coefficient of the motor in the stopped state is set to 0.

Step S134: it is determined whether the target braking torque of the braking system is greater than a recovery torque limit for the motor in an operating state.

Step S135: if so, determining the recovery torque limit value as the execution torque of the motor in the running state, and determining the hydraulic compensation torque according to the difference value between the target braking torque and the recovery torque limit value.

Step S136: if not, the target braking torque is determined as the execution torque of the motor in the running state.

The power disengaging device executes a disconnection action after receiving a corresponding instruction, so that the power system adopts a two-drive mode to provide driving power. During the drive mode switching process, if the control system receives a request for braking recovery torque sent by the braking electric control system, the braking electric control system sends out information of a motor recovery torque required value (namely, target braking torque) at the moment, and sends out information that the current torque proportionality coefficient of the working motor is set to 100%, and the current torque proportionality coefficient of the standby motor is set to 0, so that the target braking torque is distributed on the corresponding shaft of the working motor. If the power system adopts a rear drive mode, the target braking torque is distributed on the rear axle. Meanwhile, the control system can send an execution instruction to the power electric control system, so that the power electric control system controls the working motor to recover the braking energy of the vehicle and convert the braking energy into electric energy.

Before the control system sends an execution command, the control system acquires a target braking torque of the braking system and a recovery torque limit value of the working motor, and compares the target braking torque with the recovery torque limit value. Based on the comparison result, step S135 or step S136 is selectively performed.

And if the target braking torque is smaller than or equal to the recovery torque limit value of the working motor, the target braking torque is the execution torque of the working motor, so that the working motor brakes and decelerates the vehicle according to the execution torque, and the braking energy is recovered. If the target braking torque is greater than the recovered torque limit of the work motor, the recovered torque limit is the execution torque of the work motor, and a hydraulic compensation torque is determined based on the difference between the target braking torque and the recovered torque limit, and is taken as the execution torque of the hydraulic brake, so that the hydraulic torque is provided through a hydraulic braking function to perform braking force compensation.

In some embodiments, as shown in fig. 1 and 4, after the step of determining whether the power system is faulty in step S11, the braking energy recovery control method further includes the steps of:

Step S141: if the power system is faulty, a command for a disconnection operation is sent to a power disconnection device of the vehicle to stop the faulty motor of the power system, the non-faulty motor of the power system is operated, and the recovery torque capacity state of the faulty motor is set as a fault.

Step S142: zero out the execution torque of the failed motor and send a hydraulic braking command to compensate for the reduced recuperation torque.

If the driving mode is required to be switched from the four-drive mode to the two-drive mode due to the failure of the motor of the power system, the control system can timely judge that the power system has the failure condition and send out a control command to enable the power disengaging device to conduct the disconnection action, so that the motor in the failure state in the power system is stopped, and the motor in the good state in the power system continues to operate.

At this time, the power electronic control system sets the state of the motor which is stopped to be a fault state, and sets the recovery capacity state of the motor which is stopped to be a fault state, so that the motor cannot recover braking energy. And after receiving the corresponding fault state information, the brake electric control system clears the recovery torque of the motor which stops running. And the braking electric control system can send a hydraulic braking instruction to a hydraulic brake of the vehicle, so that the hydraulic brake brakes and decelerates the vehicle, and the lost motor recovery torque is compensated by the hydraulic braking function.

In addition, due to the failure condition of the power system, even if the driving mode switching is received later, the four-wheel drive mode is not switched. Even if the four-wheel drive mode can be switched, the failed motor is not started for braking energy recovery. Further, since the state of the motor that is stopped is displayed as a failure, maintenance personnel can rapidly develop an overhaul maintenance work for the failed motor.

In some embodiments, as shown in fig. 1 and 5, after determining whether the current braking energy recovery process is finished in step S12, the braking energy recovery control method further includes the steps of:

Step S151: if the current braking energy recovery process is not finished, determining the sub-target braking torque of each motor according to the current target braking torque of the braking system and the current torque proportion coefficients of the two motors of the power system.

Step S152: the magnitude of the sub-target braking torque and the recovery torque limit value for each motor is determined.

Step S153: if the sub-target braking torque is greater than the recovery torque limit, determining the recovery torque limit as an execution torque of the corresponding motor, and determining a hydraulic compensation torque according to a difference between the sub-target braking torque and the recovery torque limit.

Step S154: and if the sub-target braking torque is smaller than or equal to the recovery torque limit value, determining the sub-target braking torque as the execution torque of the corresponding motor.

During the running of the vehicle in the four-wheel drive mode, the power electronic control system sets the recovery torque capacities of the two motors of the front and rear axles to actual capacity values, namely the recovery torque limit values. If the brake electric control system sends out a request for braking energy recovery at this time, the brake electric control system sends out a motor recovery torque demand value, namely a target braking torque, and meanwhile, the current torque proportion coefficient of each motor is set to be an actual demand value, for example, the torque proportion coefficient of the motor corresponding to the front shaft is a, and the torque proportion coefficient of the motor corresponding to the rear shaft is b, wherein a+b=100%.

In the process of effectively recovering the braking energy of the vehicle by the two motors of the front shaft and the rear shaft, if a request for switching from the four-drive mode to the two-drive mode is received at the moment, whether the power system fails or not and whether the current braking energy recovery process is finished or not are sequentially judged. If the power system does not have faults, and the brake electric control system detects that the current brake energy recovery process is still continuous, the control system does not temporarily execute the switching of the driving mode, but acquires the target brake torque required to be provided by the brake system, and the corresponding recovery torque limit values and the current torque proportionality coefficients of the two motors of the front shaft and the rear shaft.

The control system then obtains a sub-target braking torque, i.e., a recovered torque distribution value, for each motor based on the product of the target braking torque and the current torque scaling factor for each motor. Next, a magnitude comparison of the sub-target braking torque and the recovered torque limit value is made for each motor. Step S153 or step S154 is selectively performed according to the comparison result.

If the sub-target braking torque is larger than the recovery torque limit value, namely the motor cannot fully bear the sub-target braking torque and exceeds the recovery torque capacity of the motor, the power electronic control system sets the execution torque of the motor as the recovery torque limit value, and obtains hydraulic compensation torque according to the difference between the sub-target braking torque and the recovery torque limit value, so that the hydraulic brake provides hydraulic compensation torque.

If the sub-target braking is less than or equal to the recovery torque limit, i.e., indicates that the motor is capable of fully assuming the sub-target braking torque, the power electronic control system sets the execution torque of the motor to the sub-target braking torque.

In some embodiments, as shown in fig. 1 and 7, in step S11, specifically, before the step of determining whether the power system is faulty, the braking energy recovery control method further includes the steps of:

Step S1: the current driving mode is monitored in real time.

Step S2: and judging whether the current driving mode is a two-drive mode or not.

Step S3: if so, the recovery torque capacity of the motor in the running state of the power system is set as the recovery torque limit value, and the recovery torque capacity of the motor in the stopped state of the power system is set as zero.

Step S4: if not, the recovery torque capacity of both motors of the power system is set as the recovery torque limit value.

In the process that the vehicle runs on the road surface, the control system can monitor the current driving mode of the vehicle in real time and judge whether the driving mode is a two-drive mode or a four-drive mode.

When the driving mode is set to the two-drive mode (generally defaulting to the rear-drive mode), in the power system, only one motor is in an operating state, and then the power electronic control system sets the recovery torque capacity of the working motor to an actual capacity value, namely, the recovery torque limit value, and sets the recovery torque capacity of the standby motor to zero. At this time, if a request for braking energy recovery is received, the power system can only use the working motor to perform braking energy recovery, and the braking electric control system sets the torque proportionality coefficient borne by the working motor to 100% and the torque proportionality coefficient borne by the standby motor to 0. During braking energy recuperation, the work motor may have its lesser of the recuperation torque limit and the target braking torque as the execution torque.

When the driving mode is set to the four-wheel drive mode, in the power system, both motors of the front shaft and the rear shaft are in running states to provide running power for the vehicle, and then the power electric control system sets the recovery torque capacity of both working motors as the recovery torque limit value. At this time, if the braking electric control system sends out a braking energy recovery request, the power system can complete braking energy recovery by using two working motors at the same time, and the braking electric control system can set the torque proportionality coefficients born by the two working motors as actual required values.

In some embodiments, as shown in fig. 1, 7 and 8, in step S3, specifically, after the step of setting the recovery torque capacity of the motor in the running state of the power system to the recovery torque limit value and setting the recovery torque capacity of the motor in the stopped state of the power system to zero, the braking energy recovery control method further includes the steps of:

step S5: in the braking energy recovery process of a braking system of a vehicle, if the requirement of switching a driving mode of the vehicle from a two-drive mode to a four-drive mode is received, the switching requirement of the driving mode is responded, and the recovery torque capacity of two motors of a power system is kept unchanged.

Step S6: and when the driving mode is switched, the recovery torque capacity of one motor of the power system is adjusted from zero to the recovery torque limit value.

During the running of the vehicle in the two-drive mode, the control system monitors in real time whether there is a request for brake recovery torque. If there is a request for brake recovery torque, then normal brake energy recovery operations are performed. When the vehicle is in a braking energy recovery state, if the control system receives a switching requirement of a driving mode so as to switch the two-driving mode to the four-driving mode, and under the condition that other mode switching conditions are met, the power system can start switching operation of the driving mode.

At this time, the power electronic control system sets the current state to be in the two-drive mode switching four-drive mode, in this process, the power electronic control system can keep the recovery torque capacities of the two motors in the power system without change, specifically, the recovery torque capacity of the working motor is the recovery torque limit value, the recovery torque capacity of the standby motor is zero, and the standby motor is ready to run and is converted into the working motor.

When the driving mode is switched, the power electronic control system sets the driving mode to be a four-wheel driving mode. When the four-wheel drive mode is successfully switched, the power electric control system can adjust the recovery torque capacity of the standby motor from zero to the recovery torque limit value, and meanwhile, the standby motor becomes a working motor to provide power for a vehicle and also has the capacity of recovering braking energy.

In some embodiments, as shown in fig. 1, 7, 8 and 9, in step S6, specifically, after the step of adjusting the recovery torque capacity of one of the motors of the power system from zero to the recovery torque limit after the driving mode is switched, the braking energy recovery control method further includes the steps of:

step S7: and if the current braking energy recovery process is not finished, determining the execution torque of the two motors according to the recovery torque limit value of the two motors of the power system, the current torque proportion coefficient and the current target braking torque of the braking system.

In the process of switching the two-drive mode to the four-drive mode, the vehicle is in a braking energy recovery state, when the two-drive mode is successfully switched to the four-drive mode, the current braking energy recovery process is still continued, and two motors of a front shaft and a rear shaft in the power system have braking energy recovery capability. Then, the brake recovery torque can be distributed to the front and rear axles according to the actual recovery capacity limit value of the current two motors and the ideal front and rear axle braking force of the current vehicle, specifically, the recovery torque distribution value of each motor is obtained according to the current target brake torque of the brake system and the current torque proportional coefficients of the two motors of the front and rear axles, then the execution torque of the motor is determined according to the recovery torque distribution value and the smaller value of the recovery torque limit value, and the power system can enable the motor to recover the brake energy of the vehicle according to the execution torque.

The invention is suitable for an electric four-wheel drive vehicle type, under the condition of not increasing hardware parts of the vehicle, a power system and a braking system of the vehicle with double motors and four wheels are coordinated and controlled through a unique control strategy, not only can realize that the driving mode of the vehicle is switched between a four-wheel drive mode and a two-wheel drive mode through a power disengaging device, but also can enable the switching function of the driving mode and the braking energy recovery function to be coupled and cooperatively controlled, and the corresponding recovery torque distribution strategy of front and rear axles is formulated according to different driving modes and vehicle states through the real-time monitoring of the switching state of the driving mode and the braking recovery torque request state, so that the problems that the recovery torque of the motor of the whole vehicle is instantaneously reduced, the braking hydraulic pressure cannot be timely supplemented, and deceleration loss or vehicle shrugging occurs can be solved, and the driving safety and the comfort of the vehicle can be improved; meanwhile, the efficiency of braking energy recovery is improved by matching with the driving mode switching process of the vehicle, and the energy consumption is reduced.

Based on the same inventive concept, corresponding to the braking energy recovery control method of the first aspect embodiment of the present invention, the second aspect embodiment of the present invention provides a braking energy recovery control system.

As shown in fig. 1 and 10, the braking energy recovery control system according to the embodiment of the second aspect of the present invention includes a judging unit, a recording unit, and a responding unit.

Wherein the judging unit is capable of executing step S11 and step S12 in the braking energy recovery control method according to the embodiment of the first aspect of the present invention. Specifically, the judging unit is used for judging whether the power system fails or not if the requirement of switching the driving mode from the four-wheel drive mode to the two-wheel drive mode is received in the braking energy recovery process of the braking system of the vehicle. And the judging unit is also used for judging whether the current braking energy recovery process is finished if the power system has no fault.

The judging unit can judge the faults of the power system after acquiring the related information of the power system, such as the working state and the fault state, and give out the fault result. And the judging unit can judge the progress of the braking energy recovery process after acquiring the opening information of the brake pedal, and give a result of whether the braking energy recovery process is finished.

The recording unit is capable of executing step S12 in the braking energy recovery control method according to the embodiment of the first aspect of the present invention. Specifically, the recording unit is configured to record a switching requirement of the driving mode when determining whether the current braking energy recovery process is finished. The recording unit can store the data of the switching requirement of the driving mode so as to be read and executed by the following response unit.

The response unit is capable of executing step S13 in the braking energy recovery control method according to the embodiment of the first aspect of the present invention. Specifically, the method is used for responding to the switching requirement of the driving mode if the current braking energy recovery process is finished. When the judging unit gives a corresponding judging result, if the current braking energy recovery process is finished, the response unit reads the switching requirement data temporarily stored before the recording unit and executes the switching operation of the driving mode.

It is understood that the braking energy recovery control system may be integrated with the control system, the braking electronic control system and the power electronic control system of the vehicle. And information transmission is carried out among the control system, the braking electric control system and the power electric control system.

A vehicle according to an embodiment of a third aspect of the present invention includes a vehicle body and a brake energy recovery control system as in the embodiment of the second aspect, the brake energy recovery control system being provided on the vehicle body. The braking energy recovery control system can perform information interaction with the power system and the braking system to realize the braking energy recovery control method of the embodiment of the first aspect.

Specifically, the braking energy recovery control system may include components such as a vehicle controller, a motor controller, a brake controller, and the like. The vehicle may be a private car such as a sedan, SUV, MPV, or a pick-up card. The vehicle may also be an operator vehicle such as a minibus, bus, minivan or large trailer, etc. The vehicle can be a new energy vehicle, such as a hybrid electric vehicle, and a pure electric vehicle.

As shown in fig. 11, an electronic device according to a fourth aspect of the present invention includes: at least one processor, memory, input/output interfaces, communication interfaces, and a bus. Wherein the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the braking energy recovery control method as an embodiment of the first aspect. The memory, the at least one processor, the input/output interface and the communication interface are communicatively coupled to each other within the device via a bus.

It will be appreciated that the processor may be implemented in the form of a general purpose CPU (i.e. central processing unit), microprocessor, or one or more integrated circuits, etc. for executing a relevant computer program for implementing the braking energy recovery control method according to the embodiments of the first aspect.

The memory mainly comprises a memory program area and a memory data area, wherein the memory program area can store an operating system and at least one application program required by functions; the storage data area may store data created according to the use of the terminal, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some examples, the memory may further include memory remotely located with respect to the processor, which may be connected to the device via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The input/output interface is used for connecting the input/output unit to realize information input and output. The input/output unit may be provided as a component in the device or may be external to the device to provide the corresponding functionality. The input unit may include a touch screen, a microphone, various types of sensors, etc., and the output unit may include a display, a speaker, a vibrator, an indicator lamp, etc.

The communication interface is used for connecting the communication unit so as to realize communication interaction between the device and other devices. The communication unit can realize the communication function in a wired mode or a wireless mode.

A bus includes a path to transfer information between elements of the device, such as a processor, memory, input/output interfaces, and communication interfaces.

A computer-readable storage medium according to an embodiment of the fifth aspect of the present invention has stored thereon a computer program which, when executed by a processor, implements the braking energy recovery control method as in the embodiment of the first aspect.

The computer-readable storage media of embodiments of the present invention may take the form of any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium may be, but is not limited to: an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In embodiments of the present invention, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, fiber optic cable, RF, etc., or any suitable combination of the foregoing.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A braking energy recovery control method characterized by comprising the steps of:

2. The braking energy recovery control method according to claim 1, characterized by comprising the steps of:

3. The braking energy recovery control method according to claim 2, characterized by further comprising the step of, in response to a switching demand of the drive mode:

4. The braking energy recovery control method according to claim 1, characterized in that after the determination of whether the power system has failed, the braking energy recovery control method further includes the steps of:

5. The braking energy recovery control method according to claim 1, characterized in that after the determination as to whether the current braking energy recovery process is ended, the braking energy recovery control method further includes the steps of:

If the current braking energy recovery process is not finished, determining sub-target braking torque of each motor according to current target braking torque of the braking system and current torque proportion coefficients of two motors of the power system;

6. The braking energy recovery control method according to claim 1, wherein the determining whether the current braking energy recovery process is ended includes the steps of:

if yes, judging that the current braking energy recovery process is finished;

7. The braking energy recovery control method according to claim 1, characterized in that before the determination of whether the power system has failed, the braking energy recovery control method further includes the steps of:

Monitoring a current driving mode in real time;

judging whether the current driving mode is a two-drive mode or not;

8. The braking energy recovery control method according to claim 7, characterized in that after setting the recovery torque capacity of the motor in the running state of the power system to a recovery torque limit value and setting the recovery torque capacity of the motor in the stopped state of the power system to zero, the braking energy recovery control method further comprises the steps of:

9. The braking energy recovery control method according to claim 8, wherein after the recovery torque capacity of one of the motors of the power system is adjusted from zero to a recovery torque limit value when the driving mode is switched, the braking energy recovery control method further includes the steps of:

10. A braking energy recovery control system, characterized by comprising:

11. A vehicle comprising a vehicle body and the braking energy recovery control system according to claim 10, the braking energy recovery control system being provided on the vehicle body.

12. An electronic device, comprising:

At least one processor; and

A memory communicatively coupled to the at least one processor; wherein the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the braking energy recovery control method according to any one of claims 1 to 9.

13. A computer-readable storage medium, on which a computer program is stored, characterized in that the program, when executed by a processor, implements the braking energy recovery control method according to any one of claims 1 to 9.